A submersible power plant is known in the art from EP 1816345. The power plant in EP 1816345 comprises a vehicle comprising one wing with a nacelle comprising a turbine and generator attached to the wing. The power plant is arranged to move in a predetermined trajectory by means of a fluid stream passing the wing.
A winged body moving through a fluid, experiences induced drag. The induced drag reduces the efficiency of the wing and decreases the lift force. At the tips of the wing fluid flows from the underside of the wing to the top side of the wing creating wing tip vortices, reducing the effective angle of attack of the wing. The induced drag of the wing from the fluid flowing over the wing thus leads to that the wing must have a large area in order to generate a desired lift, i.e. the induced drag reduces the overall efficiency of the wing. The vehicle of the power plant of EP 1816345 operates in tidal streams which can vary greatly in velocity. In order for the fluid stream to propel the vehicle in low velocity streams, the wing of the vehicle of the power plant of EP 1816345 needs a large planform area to generate the lift needed to achieve the desired vehicle velocity. This leads to that a power plant can be difficult both to manufacture and to handle.
EP 1816345 discusses the possibility of having a vehicle comprising two or more wings arranged on top of each other, separated by means of spacer elements. Having two wings on top of each other does not address all of the above mentioned problems, due to that such a solution leads to large pressure gradients over the wings reducing the effectiveness of the wings. There is thus a need for an improved submersible power plant.